Boeing's 737 Max Targets Fuel Efficiency

An extended tail cone, engine-wing integration, and updates to flight and electronics controls are new features designed to help Boeing’s next-generation 737 Max airliner meet fuel efficiency goals.

Boeing unveiled these and other design features for the forthcoming 737 series Wednesday. The features as part of its plans to optimize the performance of the airliner’s key feature: the CFM International LEAP-1B engine, which is larger and more efficient than those used in previous members of the 737 family.

Boeing is hoping for a fuel-burn improvement of 10-12 percent from the 737 Max, which is expected to be available in 2017. The decision to focus on a fuel-efficient design for the jet is a response to the needs of a financially strapped airline industry grappling with rising oil prices. Sixteen customers already are lined up to use the new planes, including American Airlines and Southwest, according to Boeing.

Boeing has made a number of design decisions for its 737 Max to promoteone of the company's main goals for the next-generation jet: fuel efficiency.(Source: Boeing)

Specifically, the company said changes to the tail and wing design (including a feature borrowed from Boeing’s plans for its 787 Dreamliner) should help improve the 737 Max’s performance. To reduce drag on the jet, Boeing will extend its tail cone and thicken the section above the elevator to steady the airflow. The company also is integrating the airliner’s engine with the wing -- a design that’s similar to the Dreamliner.

To accommodate the larger engine fan and keep the plane's ground clearance the same as the current 737s, Boeing said it will install a new pylon and strut, along with an eight-inch extension to the nose gear. Changes to the flight control and electrical system also are on tap to support fuel efficiency. The 737 Max flight controls will include fly-by-wire spoilers, which will save weight by replacing a mechanical system. The airliner also should gain fuel efficiency from an electronic bleed air system that will optimize cabin pressurization and ice protection systems.

Boeing is planning other minor design changes to accommodate the increased passenger and freight loads the 737 Max’s larger engine will allow, including reinforcing the main landing gear, wing, and fuselage. Another feature that may end up in the final design is a wing tip revision that is undergoing wind-tunnel tests, according to Boeing. The company will continue to work on optimizing the 737 Max design through mid-2013 to further tweak performance.

The improvements in effeciency have been incremental in the 737. The passenger capacity, and altitude have increased significantly over the years. I imagine it is 40% more efficient than the old 737-100. An improvement of 10%-12% above the last generation is quite an accomplishment.

Rob, 10-12% is a lot for commercial aircraft, compared to cars, for several reasons, primarily the math: a commercial plane is a lot bigger, and has a zillion more parts, which are sourced from many different component manufacturers. Also, a lot of materials lightweighting has already been done in aircraft, for several decades now, so there's proportionately less and less that can be changed or redesigned from that standpoint. Lightweighting efforts in much smaller and simpler cars are much more recent, so there's still a lot of proportionately bigger changes that can be made, and many of the big gains in cars have come from lightweighting materials and related redesigns.

Yes, Chuck, that's a significant advance in less than 15 years. What do you think the changes are? Do you expect it to be gradual? Will it require creating a different mix of models to emphasize smaller, more efficient cars? What affect will that have on the buying public? Would a Republican administration strip away those requirements?

Given that Kenish, I can understand why 10 to 12 percent is a significant number. It just seems small comparred to the kind of efficiency gains we're anticipating from the auto industry for the coming years. I can see it's a matter of scale.

@Rob- Actually 10-12% reduction in fuel burn is huge! For example the winglets that are being retrofitted to airliners create a 2-3% reduction in fuel burn. That seems minor but the airlines are willing to pay about $300k per plane for the retrofit. (Someone may have more accurate cost figures).

Fuel efficiency improvements mean less fuel cost (#1 expense for airlines), and also allows more payload and longer range routes. Additional payload capability adds up to several hundred dollars revenue per pound, annually for a 737-class airplane.

I just watched a movie about American (they must have said "largest airline in the world" at least two dozen times). AA is attaching extended tail cone's on their existing fleet themselves since the cost reduction (from having Boeing do it) was substantial. That implies that the fuel savings from that change alone is worthy of implementation. Although, I wonder what liability they are taking on by doing it themselves.

I also agree that 10% is a substantial number. With the amount of fuel they go through, the dollar savings will be HUGE over the lifetime of the airframe. Also, with airline margins as slim as they are, any improvement could be the difference between chapter 11 and profitability.

There are many efficieny improvements on this airpolane over the 40 year history of the plane. One of the more interesting aspects is the ability to retrofit many onto the older aircraft.

The 737 is arguably the most popular commercial aircraft ever. Wtih over 7000 delivered and orders for more than 2500 more it will soon pass the 10K delivery mark.

The ability of Boeing engineers to continuously improve the design and performance is testament to not only their ingenuity but also to a great design.

The new and improved wingtips are one of the more noticeable improvements. The blended engine and wing design is apparent to those with a more discerning eye.

For a long time the engines were seperated from the wing structure as a safety feature when the engines were not so reliable. The improved ability to service a pylon mounted engine was also a significant consideration. As the reliability and performance of the engines improved the aerodynamic advantages of a blended engine and wing became more attrractive.

A similar blending of the wing and body has also been considered. I suspect the manufacturing considerations are much more significant in a blended wing and body.

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